Feat: admin refactor

[qianxuege]

Name of PR:

1. Issue

Link to the associated GitHub/Notion issue:

• refactor admins table into admins and admin_categories
• modified role description
  • admin: has admin access to the related categories in the specified org
  • manager: has admin access to all categories in the specified org
  • website_manager: has admin access to all categories in all orgs

2. Changes

What changes did you make to resolve the issue?

• modified models.py file
• next steps:
  • fix all functions in models/admin.py to adhere to the new models
  • fix all api endpoints that called the functions in models/admin.py
  • alembic upgrade for all databases

Does your change introduce new dependencies to this project? If so, list here.

• No

3. Validation

How did you trigger the change to show that it is working?

Attach screenshot(s) of the logs and UI demonstrating the change.